docs: def _get_deltas(self, rake):
          """
          Return the value of deltas (delta_R, delta_S, delta_V, delta_I),
          as defined in "Table 5: Model 1" pag 198
          """
          # delta_R = 1 for reverse focal mechanism (45<rake<135)
          # and for interface events, 0 for all other events
          # delta_S = 1 for Strike-slip focal mechanisms (0<=rake<=45) or
          # (135<=rake<=180) or (-45<=rake<=0), 0 for all other events
          # delta_V = 1 for TVZ events, 0 for all other events
          # delta_I = 1 for interface events, 0 for all other events
  
          # All deltas = 0 for Model 3: Deep Region, pag 198
  
          delta_R, delta_S = 0, 0
          delta_V, delta_I = 0, 0
  
          if rake > 45.0 and rake < 135.0:
              delta_R = 1
  
          if (rake >= 0.0 and rake <= 45.0) or \
             (rake >= 135 and rake <= 180.0) or \
             (rake >= -180.0 and rake <= -135.0) or \
             (rake >= -45.0 and rake < 0.0):
              delta_S = 1
  
          return delta_R, delta_S, delta_V, delta_I